Mobile communications, by definition, provide communications services to devices that move through space. Mobile communications services must adapt to new device locations as the devices move. Effective adaptation is one aspect of providing quality mobile communications service.
Mobile communications services adapt to new device locations in a variety of ways such as switching communications channels and adjusting device, transmission, and network settings. A handoff is one example of adapting to new device locations. In mobile telecommunications, the term handoff refers to a process of transferring an ongoing call or data session from one transmissions channel to another. There are a variety of reasons why a handoff might be conducted, including for example, when a mobile communications device in a cellular network is moving away from an area covered by a first cell, and entering an area covered by a neighboring cell. In this scenario, the call or data session may be transferred to the neighboring cell in order to avoid call degradation or termination when the mobile device moves outside the range of the first cell.
One or more current signal quality parameters may be monitored to decide when a handoff should be made. Current signal quality parameters may include, for example, current received signal power, current received signal-to-noise ratio, current bit error rate (BER), current block error/erasure rate (BLER), current received quality of speech (RxQual), current distance between the mobile device and a base station, and other current signal quality parameters. In cellular communications, a mobile device and base stations of neighboring cells monitor each other's signals and the best target candidates are selected among the neighboring cells, based on current signal quality parameters. The handoff may be requested by the mobile device, by a base station associated with the first cell, or by a base station of a neighboring cell.